Edwin edser



' London, England,

acid UNITED STATES PATENT oEEIoE.

EDWIN EDSER, OF BROCKLEY, LONDON, AND HENRY LIVINGSTONE SULMAN, OF LONDON, ENGLAND.

CONCENTRATION OF ORES.

To all whom it may camera:

Be it known that we, EDWIN EDsER, a subject of the King of England, residing at Brockley, London, England, and HENRY LIVINGSTONE SULMAN, a subject of the King of England, residing at 44 London iVall,

iave invented certain new and useful Improvements in the Concentration of Ores, of which the following i a specification.

This invention is for improvements in or relating to the concentration of ores, and it relates more particularly to flotation separation, such as by the agitation-froth process described, for example, in the prior United States Patents No. 835,120 of November 6, 1906, No. 962,67 8. of June 28, 1910, and No. 1,064,723 of June 17, 1913.

Hitherto it has been found difficult in many cases to obtain a good separation of 'sulfid and other mineral substancesby the agitation-froth process from ores whose gangue contains such materials as clay, slate, mica, kaolin and calcite. In such ores the tendency is for the gangue material to be floated together with the mineral, and it is an object of the present invention to overcome this difliculty.

According to the present invention in the concentration of ores, the said ores are subjected either before or during the flotation separatlion process .to the action of silicic The proportion of the silicic acid sol most suitable must be determined by experiment on the particular ore and in relation to the frothing agent and the nature of the water employed, but, reckoned in terms of pure SiO,, from 1 to 10 lbs. per ton of ore has been found to work well on a large number of sulfid ores with gangues of the nature above specified.

The silicic acid sol may be prepared by adding sodium silicate to sulfuric acid so as to neutralize the silicate, care being taken to avoid the formation of a gel.

The ore may be treated with the s1l1c1c acld sol in a preliminary sta e, for example, by milling or by digesting t e finely ground ore with the dilute sol, or the latter may be added to the pulp during the flotation process, for example contemporaneously with the mineral-frothing agent. Examples of the application of this invention will now be described.

Specification 01 Letters Patent.

Patented Dec. 30. 1915.

Application filed May 12, 1917. Serial No. 168,080.

Example 1 The ore material taken was the iinely ground .waste resulting from the previous water concentration of a blendegalena ore; it carried much free quartz and a large proportion of calcite as angue material W 11011 gave rise to much gifliculty in froth flotation. The silicic acid sol was prepared by dissolving 5 grams of water glass in 400 oils. of Water, exactly neutralizing it with sulfuric acid, and then diluting to 500 ccs. 400 grams of the ore which assayed lead 7.50% and zinc 5.26% were mixed with 1600 cos. of water to which 90 cos. of the silicic acid solution was added, this being equivalent to 11 lbs. of silica in the state of silicic acld per ton-of ore. Eucalyptus oil amountmg to 1%.lbs. per ton of ore was added and the whole agitated and aerated for the formation of a froth.

The concentrate thus obtained amounted to 25.7% of the ore taken and assayed lead 20.3% and zinc 12.9%. giving a recovery of 52.25% of the lead and 61.2% of the zinc.

A second experiment made under pre-' cisely similar conditions but omitting the silicic acid resulted in obtaining a concentrate amounting to 32.5% of the ore, assay-- ing lead 16.00% and zinc 8.73%, which is equivalent to an extraction of 52% of the lead and 41.9% of the zinc.

The employment of silicic acid thus not only increased the recovery of the zinc but ore from the Djebel Ressas mine in North Africa containing 14.0% zinc and 12.2%

lead in the form of sulfids, and having a gangue consisting mainly of calcite, the assay giving 31.0% calcium oxid and 2.5%

insolubles, was crushed to pass through mesh and mixed with 5000- grams of tap water. Silicic. acid sol was added at the rate of 1.1 lbs. of silica per ton of ore. A

blast furnace creosote oil at the rate of irds lb. per ton of ore, and pine tar at the rate of ?;rd lb. per ton of ore were added and the mixture was agitated and aerated for the formation of a froth of the metalliferous particles. The froth removed during a 20 minutes run weighed 541 grams and assayed 27.3% zinc and 25.8% lead. The tailings assayed 2.9% zinc and 0.9% lead, thus giving a recovery of 88.5% of zinc and 95.8%

lead. By no other treatment have such good 1.7 lbs. of silica per ton of ore and a blast furnace creosote oil at the rate of 1.3 lbs. per ton of ore were added to the pulp in the flotation machine and the whole agitated and aerated for the formation of a froth. The concentrates recovered .were found to weigh 231 lbs, and assayed 17.1% copper, While the tailings weighed 869 lbs. and assayed 0.49% copper. The recovery was therefore 81.6%.

In some cases certain salts added to the pulp, together with the silicic acid sol give a beneficial effect. sulfate may in some cases be .added together with silicic acid sol at the rate of 1 to 3 lbs. per ton of ore.

In some cases metallic carbonates in'ores may be successfully recovered by the process according to the present invention.

What we claim as our invention and desire to secure by Letters Patent is 1. An ore-concentrating process wl1ich consists in separating the constituents of an ore pulp by aid of the addition of silicic acid sol to the pulp.

2. The process of concentrating ores by flotation separation which consists in introducing silicic acid sol into an ore pulp to influence the flotation tendencies of the ore constituents, and separating said constituents by flotation.

3. The process of concentrating ores by bubble flotation which consists in aerating an ore pulp to form mineral-carrying bubbles therein and influencing the mineral selectivity o'ffsaid bubbles by theaddition For example sodiun'r of silicic acid sol to the pulp and removing the mineral constituents of the pulp carried by saidbubbles.

4. The process of concentrating ores by, froth-flotation separation which consists in aerating an ore pulp to form a. mineral froth and influencing the mineral-froth formation by the addition of silicic acid sol to the pulp and removing the froth.

5. An ore-concei'itrating process which consists in separating the constituents of an ore pulp by aid of the addition of silicic acid sol to the pulp together with sodium sulfate.

6. The process of concentrating ores by flotation separation which consists in introducing silicic acid sol into an ore pulp together with sodium sulfate to influence the flotation tendencies of the ore constituents, and separating said constituents by flotation.

7. The process of concentrating ores by bubble flotation which consists in aerating an ore pulp to form mineral-carrying bubbles therein and influencing the mineral selectivity of said bubbles by the addition of silicic acid so] to the pulp together with sodium sulfate and removing the mineral constituents of the pulp carried by said bubbles.

8. The process of concentrating ores by froth-flotation separation which consists in aerating an ore pulp to form a mineral froth and influencing the mineral-froth formation by the addition of silicic acid sol to the pulp together with sodium sulfate and removing the froth.

In testimony whereof we have signed our names to this specification in the of two subscribing witnesses.

EDWIN EDSER. HENRY LIVINGSTONE SULMAN.

Witnesses:

HAROLE': CHARLES HANKINS, WILLIAM JAMES WALTON.

presence 

